Piston assembly



aptD 13, E966 W. F. Dimmi@ @pwm PSTON ASSEMBLY Filed NOV. 27, 1964 United States Patent O 3,272,091 PISTGN ASSEMBLY Walter F. Dziedzic, Detroit, Mich., assignor to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Nov. 27, 1964, Ser. No. 414,945 Claims. (Cl. 92-152) This invention relates to a means or method for forming a two-diameter piston and/ or connecting two or more separate pistons or piston-like members so as to enable reciprocation thereof without binding when the cylinders or passages therefor are axially misaligned.

'Ihere are many applications wherein a two-diameter piston is required. When such a piston is made in one solid piece, it is necessary that the adjoining cylinders, wherein the two-diameter piston is to be slidably mounted, be perfectly aligned. However, machining perfectly aligned adjoining chambers in a body or housing, in order to prevent the two-diameter piston from binding therein, may be very time-consuming and expensive.

Likewise, when a two-diameter or other solid piston must be slidably mounted in adjacent chambers Iformed in separate bodies, the assembly operation to perfectly align the chambers may be very cumbersome and perhaps impossible, particularly if lthe tolerances between the outer diameters of the pistons .and the inner diameters of the chambers are close.

Accordingly, a primary object of this invention is to provide a means or method for employing a two-diameter or compound piston assembly in adjacent cylinders formed in one or more sections, without requiring absolute axial alignment of the cylinders.

A further object of the invention is to provide a twodiameter or compound piston assembly which may be slidably operated in adjoining cylinders, without binding when the cylinders are axially out of alignment within predetermined limits.

A more specific object of the invention is to provide an assembly comprising a pair of pistons which are interconnected by a rod having the ends thereof bent perpeny dicular to the axis thereof and to each other, the rod being adapted for insertion int-o axial and transverse openings formed in the adjacent ends of the two pistons, thereby permit-ting radial and/or angular movement between said pistons.

Other more specific objects and advantages of the invention will become more apparent when reference is made to the following specification and the accompanying drawings wherein:

FIGU-R-E l is a side elevational view, in partial crosssection, of a compound piston assembly embodying the invention and mounted in misalig-ned cylinders formed separately.

FIGURE 2 is a perspective view of one element of the invention.

FIGURE 3 is a side elevational view, in partial crosssection, of a two-diameter counterbored cylinder application wherein the invention may .be used.

FIGURE 4 is a side elevational view in partial crosssection, of a modification of the invention.

FIGURE 5 is a side elevational view, in partial crosssection, of another modification of the invention.

Referring now to the drawings in greater detail, FIGURE 1 illustrates a pair of bodies or housings 10 and 12 which are fastened together by any suitable means, such as bolts 14. A gasket 16 may be confined between the bodies 10 and 12.

It may well be imagined that when two housings, such as housings 10 and 12, are fas-tened together, maintaining the two adjacent cylinders 18 and 20, which were formed separate-1y, in perfect axial alignment may be very diffi- ICC cult to achieve. For example, merely tightening the clamping means, such as the bolts 14, Will usually cause sufficient misalignment between the cylinders .18 and 20 so that a rigid single piece compound piston would encounter binding.

According -to the invention, such misalignment is compensated for .within predetermined limit-s, by a piston assembly 22 comprising a pair of separate pistons 24 and 26, each having extensions 28 .and 30, respectively, formed at the adjacent ends thereof. The extensions 28 and 30 include axial passages 32 and 34 and transver-se passages 36 and 38, respectively, the latter being formed through the walls of the extensions 28 and 30 t-o intersect the axial passages 32 and 34 at right angles.

A wire rod or other member 40 is used to connect the pistons 24 and 26, the end-s 42 and 44 of the rod 40 being 'bent at right angles to the axis of the rod 40 and to each other (FIGURES 1 .and 2).

The lengths and ldiameters of the axial and transverse passages 32 and 36 are such that the end 42 of the rod 40 1may be readily inserted in the piston extension 28 in the position illustrated in FIGURKE l. This is also true of the end 44 and the passages 34 and 38 of the other piston extension 30. Due to the dimensions of the passages 32, 34, 36 and 38 relative to the dimensions of the rod 40 and the ends 42 and 44, the axes of the cylinders 1'8 and 20 may be rnisaligned either radially Ior angularly, within significant limits, without adversely affecting free reciprocating movement of the pistons 24 and 26 within the cylinders 18 and 20. In other words, the cylinders 18 and 20 coul-d have `axes which either are offset from but parallel with one -another or form an included angle of less than with one another. In fact, both the offset and angled misaligned conditions could be present at the same time in .a particular assembly. The degree of misalignment would be limited only by the `size of the axial and transverse openings 32, 34, 36 and 38, relative to the diameter of the rod 40 and, at times, by the adjacent offset edges of the cylinders 18 and 20.

The same or a similar piston assembly 22 may be satisfactorily used in a housing, such as that represented generally by 46 in F'IGU'R'E 3, wherein supposedly concentric counterbored cylinders 48 and 50 are formed. It is apparent that the machining techniques employed to form the cylinders 48 and 50 may be considerably less critical when the two-diameter piston assembly 22, as compared to a rigid piston, is utilized, since, as described above, the pistons 214 and 26 will readily slide within the chambers I48 and 50 without binding, even though there is a deg-ree of radial and/or angular misalignment between the axes of the two cylinders.

Referring now to FIGURE 4, it will be noted that the assembly 22 may, for some applications, include a flanged spring retainer 52 assembled on the extension 28 and around the rod 4t) by vi-rtue of an opening 54 formed through the center of the retainer 52. A llange 56 formed on the retainer 52 serves to abut against a ledge 5'8 formed in a cylinder 60. A spring -62 is confined between the flange 56 and the adjacent face 64 of the piston 26. Such an assembly is useful when it is desired to have the pistons 24 and 26 returned to a normal position, after having been forced upwardly in the chamber 66 against the force of the spring 62, by virtue off either increased pressure below the end 68 of the piston 26 or increased vacuum above the end 70 of the piston 24. Obviously, as the pressure sub-sides or the vaccum decreases, the spring 62 will once again extend to its maximum length, as determined by the length of the rod 40, and thus move both pistons downwardly in their cylinders 60 and 66.

As illustrated in FIGURE 5, the assembly 22 may simply contain a spring 62 which is compressed between opposing faces 64 and 72 of the pistons 26 and 24, respectively. In this assembly, the outer ends 68 and 70 of the pistons 26 and 24, respectively, are maintained a constant distance apart, regardless of the tolerances between passages 36 and 38 relative to the bent ends 42 and 44, respectively. In other words, the so-called slack between the pistons 24 and 26 will be taken up by the compressed spring 62.

It is apparent that the invention provides a novel means for not only making possible a quick and easy assembly of a plurality of piston components, but further provides for a faster and less expensive machining operation of the cylinders wherein the piston assembly is to operate. The novel piston assembly may be used in adjoining cylinders which may be both radially and angularly misaligned. In summary, the piston assembly embodying the invention may be readily inserted into misaligned cylinders and will function satisfactorily therein.

It is also apparent that a piston assembly embodying the invention may be regarded either as a single piston operating in a single cylinder or as a compound piston, or a plurality of connected pistons, operating in a plurality of cylinders.

It should be further apparent that the invention may be employed in hydraulic pump or other applications wherein a long piston stroke is involved, it being diflicult to maintain the axis of a relatively long passageway perectly straight.

While four embodiments of the invention have been shown and described, it is apparent that other modifications thereof are possible Within the scope of the appended claims.

What I claim as my invention is:

1. A piston assembly for reciprocating movement within adjacent misaligned cylinders, said assembly comprising rst and second pistons, the adjacent end of each of said pistons having an extension formed thereon, each of said extensions having intersecting axial and transverse openings formed therein, and an elongated connector having the ends thereof bent to form right angles with the axis of said connector and with each other, said ends being inserted into said transverse openings.

2. The device described in claim 1 wherein a coil spring surrounding Said connector is compressed between said pistons.

3. The piston assembly for use in a cylinder having misaligned axes, said assembly comprising a plurality of piston sections connected by an elongated member, the connection of said member with each of said piston sections being such as to permit limited radial and angular displacement of the axis of one piston section with respect to the axis of the adjacent piston section, said member comprising an elongated element having laterally extending free ends, said free ends extending 90 with respect to each other and being received in openings formed in said piston sections.

4. A housing having counterbored chambers formed therein, a piston assembly slidably mounted in said counterbored chambers, said piston assembly comprising rst and second pistons, each of said pistons having an extension formed on one end thereof, intersecting axial and transverse holes formed in said extensions, an elongated connector having the ends thereof bent to form right angles with the axis of said connector and with each other, said ends being inserted into said transverse holes, and a spring compressed between said pistons around said elongated connector.

5. A housing having counterbored chambers formed therein, a piston assembly slidably mounted in said counterbored chambers, said piston assembly comprising iirst and second pistons, each of said pistons having an extension formed on one end thereof, intersecting axial and transverse holes formed in said extensions, an elongated member having the ends thereof bent to form right angles with the axis of said member and with each other, said ends being inserted into said axial and transverse holes, a spring seat mounted on one of said extensions and around said members, a flange formed on said spring seat for abutment against the end of one of said counterbored chambers, and a spring compressed between said seat and the adjacent piston.

References Cited by the Examiner UNITED STATES PATENTS 965,270 7/1910 Zelle 92-61 X 2,011,833 8/1935 Sorg 92-165 X 2,057,158 10/1936 Moitt 92-76 3,018,125 1/1962 Cain 64-15 X MARTIN P. SCHWADRON, Primary Examiner. EDGAR W. GEOGHEGAN, Examiner. I. C. COHEN, Assistant Examiner. 

1. A PISTON ASSEMBLY FOR RECIPROCATING MOVEMENT WITHIN ADJACENT MISALIGNED CYLINDERS, SAID ASSEMBLY COMPRISING FIRST AND SECOND PISTONS, THE ADJACENT END OF EACH OF SAID PISTONS HAVING AN EXTENSION FORMED THEREON, EACH OF SAID EXTENSIONS HAVING INTERSECTING AXIAL AND TRANSVERSE OPENINGS FORMED THEREIN, AND AN ELONGATED CONNECTOR HAVING THE ENDS THEREOF BENT TO FORM RIGHT ANGLES WITH THE AXIS OF SAID CONNECTOR AND WITH EACH OTHER, SAID ENDS BEING INSERTED INTO SAID TRANSVERSE OPENINGS. 